Real‐world data for the renal safety of abemaciclib combined with bisphosphonate in HR+/HER2− advanced breast cancer

OBJECTIVE: Our study evaluated the renal safety of abemaciclib plus endocrine therapy (ET) with bisphosphonate as a treatment option for hormone receptor positive, human epidermal growth factor receptor 2 (HER‐2) negative (HR+/HER2−) advanced breast cancer (ABC), especially with bone metastasis. METHODS: Data were collected from HR+/HER2− ABC patients who received abemaciclib with ET between March 2021 and May 2022 in a single medical center in China. We performed an analysis of the change in serum creatine (Cr) and creatine clearance (CrCl), time to first abnormal Cr value, and Common Terminology Criteria for Adverse Events grade of increased creatinine. RESULTS: A total of 210 patients were included in the final analysis, with a median age of 56 years and a median weight of 65 kg. Any grade laboratory‐assessing increased Cr occurred in 87.1% of patients, while CrCl rarely went down to 30 ml/min. Associations between start dose with grade of increased Cr and menopausal status with alert value, which is defined as creatinine clearance <30 ml/min, were indicated. CONCLUSION: This study shows that abemaciclib combined with bisphosphonate would be safe for renal function in HR+/HER2− ABC patients with bone metastases.